Pratt truss

The Pratt truss is named after Thomas and Caleb Pratt, Boston railroad engineers who patented the design in 1844. The Pratt and its variations are the most common design of metal truss bridges.
On a basic Pratt truss, the diagonals slope toward the center of the bridge, do not cross any verticals, and are approximately parallel. The top chord is straight and parallels the lower chord. The panels can have sub-divisions - or verticals and diagonals that don't reach from the top to bottom chord, though this can be considered a variation of the basic type.
There are many variations, or sub-types of the Pratt truss, some of which have their own name including Parker, camelback, Pennsylvania, Baltimore, and others.
It is used in bridges as a through truss, pony truss, and deck truss.

Lost Creek Bridge No. 1 (Lincoln County, Missouri)Pratt pony truss bridge over Lost Creek on Farm roadOpen to traffic

Lost Creek Bridge No. 2 (Lincoln County, Missouri)Pratt pony truss bridge over Lost Creek on Farm roadOpen to traffic

Lost Creek Bridge No. 3 (Lincoln County, Missouri)Pratt pony truss bridge over Lost Creek on Farm roadOpen to traffic

Lost River Bridge (Hardy County, West Virginia)Built 1931; rehabilitated 1994Through truss bridge over Lost River on CR 55/20Open to traffic

Lost River CR 49 (Martin County, Indiana)Built ca. 1900; Replaced 1990Bridge over Lost River on Powell Valley Rd., CR 49Replaced by a new bridge

Lost River-101 Ranch Rd. Bridge (Orange County, Indiana)Built ca. 1910Lost Pratt pony truss bridge over Lost River on 101 Ranch Road (CR 960W)Replaced by a new bridge

Lost River-Tater Rd. Bridge (Orange County, Indiana)Built ca. 1920; rehabilitated 1992Pony truss bridge over Lost River on Tater Road (CR 500E)Open to traffic

Lower Elgin Road Bridge (Bastrop County, Texas)The KCBI bid for several bridges (3 or 4--exact details TBD), including this one, was for $12,829 and was accepted by the Bastrop County Commissioners Court on May 31, 1887 (source: Bastrop County Commissioners Court meeting minutes, Vol. D. p. 270)Pratt through-truss bridge over Wilbarger Creek on Lower Elgin Road (CR 55). This road has also been known as Coats Rd.Was open to pedestrians until the flooding of Wilbarger Creek in May, 2015. As a result of the flood, the bridge sustained damage to the decking and was closed by Bastrop County.

Lower Gas Point Road Bridge (Shasta County, California)Built 1920Through truss bridge over North Fork Cottonwood Creek on Lower Gas Point RoadOpen to traffic

Lucas Grove Road Lowe Run Bridge (Muscatine County, Iowa)Lost Pratt through truss bridge over Lowe Run on Muscatine-Des Moines Shortline/Lucas Grove RoadReplaced by a new bridge

Luce Line Trail Bridge (Hennepin County, Minnesota)Built 1885 in Pearl, Illinois; Relocated to Long Lake in 1914; Relocated again 2008Pratt through truss bridge over Wayzata Boulevard on Luce Line State TrailOpen to pedestrians

M&StL - Keithsburg Lift Bridge (Mercer County, Illinois)Built 1909; Abandoned 1971; Partially lost to fire in 1981Vertical lift bridge that carried the M&StL across the Mississippi River at KeithsburgAbandoned

M&StL - Spencer Bridge (Clay County, Iowa)Built 1899; Removed 1936Lost Pratt through truss bridge over Little Sioux River on Minneapolis & St. Louis RailwayReplaced by a new bridge

MacArthur Bridge (St. Louis, Missouri)(Main design: Pennsylvania through truss)Built 1907-1917 by the City of St. Louis to break the monopoly of the Terminal Railroad Association, which controlled the two other bridges at St. Louis and charged unreasonable tolls. Automobile deck closed to traffic in 1981.Three-span through truss bridge over the Mississippi River in St. Louis, south of the Poplar Street BridgeOpen to railroad traffic only

Machia Road Bridge (Franklin County, Vermont)Built 19282 span Pratt through truss bridge over Missisquoi River on C3006 in HighgateOpen to traffic

Mackville Road Bridge (Lincoln County, Missouri)Built 1936; replaced 2004Lost through truss over North Fork Cuivre River on Mackville Road just beyond the end of Route K at BriscoeReplaced by modern bridge

Macon Bridge (Macon County, Missouri)Lost through truss bridge on a city street in MaconNo longer exists

Maddox Mill Bridge (Whitfield County, Georgia)Built sometime around 1915, abandoned in the 1930's or 40's when Chatsworth Highway was moved to it's present alignmentAbandoned pratt pony truss bridge over Coahulla Creek on old alignment of Chatsworth Highway / SR 52Abandoned on private property

Madison Ave. White River Bridge (Madison County, Indiana)(Main design: Baltimore through truss)Lost through truss bridge over White River on Madison Ave. in AndersonReplaced by new bridge

Madison Street Bridge (1st) (Multnomah County, Oregon)Built 1891 Rebuilt into second bridge 1900Lost Pratt through truss swing bridge over Willamette river on Madison Ave now Hawthorne street.Replaced by a new bridge

Madison-Milton Bridge (Jefferson County, Indiana)(Main design: Warren through truss)Built 1928-29; rehabilitated 1997, imploded August 2013Cantilevered through truss bridge over Ohio River on US 421 between Madison, IN, and Milton, KYAll main spans demolished.

Madisonville Bridge (Ralls County, Missouri)Built 1893 by St. Louis Bridge & Iron Co.; relocated to a nearby field in 2005Through truss bridge formerly over Spencer Creek on Madisonville Road just beyond the end of Route C, but now located in a field just north of its old locationRelocated to a nearby field after being purchases by a local couple. Replaced by new bridge

Magnolia Garden Bridge (Orleans Parish, Louisiana)Built in 1800s; moved to present location in 1909; restored for pedestrian use in 1989Pratt through truss bridge over Bayou St. John at Harding DriveOpen to pedestrians

Magnum Through Truss (Eastland County, Texas)Pratt through truss bridge over South Fork Leon River on RoadOpen to authorized vehicles only

Mahalasville Road Bridge (Morgan County, Indiana)Built ca. 1920 in Morgan County: Larger span moved to Yorktown in Delaware County after smaller span was destroyed by a fallen tree.Relocated pony truss bridge over Buck CreekOpen to pedestrians only

Mahanoy Creek Bridge (Northumberland County, Pennsylvania)Built 1902 by the King Bridge CompanyThrough truss bridge over Mahanoy Creek on TR 377Closed to all traffic

Main Street Bridge (Keweenaw County, Michigan)Built 1909 by the Joliet Bridge and Iron Co.Pony truss bridge over Eagle River on West Main in Eagle RiverOpen to pedestrians

Main Street Bridge (Crawford County, Pennsylvania)Built 1937; rehabilitated 1980Pratt through truss bridge over French Creek on US 6/US 19Open to traffic

Main Street Bridge (Warren County, Indiana)Built 1886, replaced in 1924Lost Through truss bridge over Wabash River on Main Street at AtticaReplaced by a new bridge with spans being relocated to various locations in Fountain County.

Main Street Bridge (Clay County, Iowa)(Main design: Pennsylvania through truss)Built 1889, span added 1901, Replaced 1915Lost Pennsylvania through truss bridge over Little Sioux River on Main Street (Now Renamed)Replaced by a new bridge

Main Street Bridge (Wright County, Iowa)Replaced 1977Lost Pratt through truss bridge over Iowa River on Main StreetReplaced by a new bridge